I have a D40 and love it. Shoot a lot, learn the camera and lens, and when you know what kind of photography you'll be doing, then consider the upgraded lenses/flashes and other items.

For some shots I set mine to manual (if I have the time to do so, as it sometimes requires a few tries to get the perfect f-stop and shutter combo for a given scene) but for a lot of stuff I set it to auto or "P" mode.

Having done it both ways, I can say that shooting in Manual (M) on a dSLR will definitely teach you a lot since you have instant feedback, but only if you're willing to carry the camera everywhere and shoot everything, five or six times, at a wide range of settings and lighting conditions. Otherwise, go with Aperture Priority (Av). You will still lose a lot of images until you get better acquainted with the camera settings and how they affect the final product, but the odds are more in your favor since manually controlling the aperture is usually more important than controlling the exposure time, which the camera will do for you in Av mode.

Just go outside on a sunny day and start shooting whatever's nearby. And aren't I glad that this is a camera thread to give context to that sentence...

Anyway, you want to understand the relationship of three things, represented with different numbers: Shutter Speed, Aperture, and ISO. Changing either one of them will affect how bright/dark your images are, AS WELL AS one other "side effect" unique to each choice. All three affect each other and you will eternally balance with them.

-Your shutter speed seems intuitively obvious: How long your shutter is open, or rather, how long your sensor is exposed to light. Measured in fractions of a second, or whole seconds or even minutes for really long exposures, but for walking around holding the thing in your hands, you're going to want numbers like 1/50 or 1/100, or even 1/1000 or 1/2000 in broad daylight. SIDE EFFECT: Shutter speed is also what you use to freeze motion. Something moving very fast will still be blurry even at 1/100th of a second. At 1/4000th, however, you might be able to freeze the subject. But getting that high of a shutter speed cuts down the amount of light you have, which leads us to...

-Aperture: How big a "hole" your sensor is being exposed to. Think of a water faucet; on low it takes forever to fill up a cup, but open it up a little and suddenly your cup runneth over in no time. Sometimes water pressure can be so strong it'll blast in your glass and splash out all over the place. With light, that last effect leads to "overexposure", when it's so bright that all you get is stark glaring whiteness, all detail of your subject gone. So you reduce the size of the hole that light (water) is going through, so it doesn't overload the sensor (cup). They call this "stopping down". One full "stop" refers to a halving or doubling of light; the water faucet becomes half or twice as strong, respectively. So the next number you have to worry about is your "f-stop", the number system that describes how "open" or "closed" your lens is. f/11 is a very small hole, and you'll probably only use this in broad daylight. Lots of zooms have a widest f-stop of 3.5; more expensive zooms will go to f/2.8; some prime lenses (lenses that don't zoom) go down to very wide f-stops like 1.8 or 1.4. Very small numbers (wide apertures) mean lots of light per unit of time: at 1/100th of a second, f/2.8 will be "twice as bright" as f/4.

SIDE EFFECT: This is a biggie, and it's Depth Of Field. This refers to how wide an area, perpendicular to the front of the lens. Narrow depth of field (DoF) has everything on one narrow plane in focus, while everything behind it or in front of it is blurry; this is a product of wide apertures (small f-numbers, like f/1.4 or f/2 or whatever) in most shooting situations. Deep DoF, or wide, or thick, or... whatever... has a very large plane of focus, at very narrow apertures (big f-numbers, like f/8, 11, 16). Although I confess, in that last photo I cheated and used a very wide-angle lens; I'll give you a note about focal length below.

-ISO is just how sensitive your camera is to light. This is a very simple one: Noise. Low ISO's mean low noise, and low sensitivity (you'll need wider apertures or longer shutter speeds unless you're in broad daylight). Noise is random data of wrongly-colored pixels. When there's less light, the camera has to "guess" more, and makes more errors based on random spikes of information in the sensor. The technical details are fascinating, but are also minutiae when discussing shooting. What you really need to understand is that the clearest, sharpest, best colored images will come at the lower ISOs. Higher ISOs make shooting in very low light possible. The D90, in my opinion, looks very good even at ISO 1600 or even, depending on the subject, 3200, but try the different settings and see what you like. You may prefer to keep it under ISO 800. I know I try to keep it at ISO 200 as much as possible.

ISO is sort of a buffer that gives you wiggle room between balancing your aperture and shutter speeds. If you really want a deep depth of field, need a high shutter speed, you have no choice but to raise the ISO (or add more light; open a window, turn on more lights, use a flash or multiple flashes... photography can get expensive really quick).

-Focal length: How "zoomed in" or "zoomed out" you are, in simplest terms. Small numbers mean a wide angle of view (how much of what's in front of you will you see) while big numbers mean a narrow angle of view, to frame really tightly on distant objects. Roughly "in the middle" (thematically, not numerically) is the "normal" range. This corresponding number is commonly viewed to be hovering around 50mm in good ol' 35 mm film parlance; for a DX camera like your D90, which has a smaller sensor, "normal" is right around 35mm. Numbers smaller than 35 are "wide", and numbers higher go into "telephoto" range.

Wider lenses, all else being equal, will also have deeper depth of field. A 15mm focal length at f/4 will have a greater range of objects in focus than a 100mm focal length at the same aperture.

Shutter speed doesn't affect depth of field, but it will affect how blurry (or otherwise) your pictures are. At 1/30th of a second, even casual movement will make blur. At 1/5th of a second, your hand holding the camera will be so jittery that the entire image will blur, unless you have a very good Vibration Reduction system in your lens.

Hmm. I wound up writing way more than I thought I would, and I'm kinda running outta steam. I know I'm only beginning to scratch the surface. Sorry for the abrupt conclusion; congratulations on the new toy! Play around with it, go take some pictures, and realize that understanding the numbers and the tools are only to facilitate your own vision. Composition will ultimately be the most important thing for you to work on, and you'll be going nuts with it once you get over what I consider to be a not too steep learning curve.

@SPOOFE --> I have to commend you on taking the time to type all that out good info and I'm sure the OP appreciated it.

@tsoulier --> It is a good camera, you might also want to take a look at the 50mm 1.8. I'm not sure if your camera is able to auto focus the lens so you will have to read up on it, but it is a great alternative to the previously recommended and much more expensive 50mm 1.4. The speedlight is also a great investment and will really help provide a more professional look to your photographs.

Good luck and as everyone else already mentioned, the more you shoot, the more you will learn the capabilities of your camera and how to achieve the look you are going for.

The AF 50mm f/1.4D is $330 new at Adorama. It should be available for less in the used market.The AF 50mm f/1.8D is $120.The AF-S 50mm f/1.8G is $212.The AF-S 50mm f/1.4G is $447.

The D90 camera does have the screwdriver mechanism to drive the focus screw on the older -D design Nikon AF lenses. It's the entry-level Nikon cameras that are only fully-functional with the newer AF-S lenses.

Actually, I highly recommend using P (program) mode instead. Just point and shoot, no worries. Forget all about the technical minutiae. If you've never photographed before, know that it's just like drawing. The simplest photographs are the ones that look best. If you use Manual, you will miss a lot of good moments that you passed by just because you were trying to recall what combination of shutter speed/ISO/aperture you need, and then you have to set it manually. Ridiculous, that is not the point of photography. Just find something interesting, find a good angle, and let the camera do the rest.

Don't go out and shoot a lot of crap ass pictures that nobody will give two flying **** about, while obsessing over "maybe i need a better lens" or "maybe I need a better camera" or "i shoot in RAW all the time" or whatever. What's important is the vision, and the composition. Just take a drawing class. You may not be able to draw, but the principles will apply, and the camera does the drawing for you anyway. The camera exists to make drawing easy. Hence, use P.

EDIT: I shoot digital when I'm practicing, or when I'm not particularly serious about the subject. When I see something I really like, though, I whip out the Nikon F5. I love that baby, got it for 180EURs. Just knowing that I am holding something incredibly expensive and professional in my hands makes me take all the more care in every shot.

Crayon Shin Chan wrote:Don't go out and shoot a lot of crap ass pictures that nobody will give two flying **** about, while obsessing over "maybe i need a better lens" or "maybe I need a better camera" or "i shoot in RAW all the time" or whatever. What's important is the vision, and the composition. Just take a drawing class. You may not be able to draw, but the principles will apply, and the camera does the drawing for you anyway. The camera exists to make drawing easy. Hence, use P.

I agree that learning to frame your image is the most important part of photography, but disagree regarding the hardware use. Focal length and aperture have a huge impact on what the final product looks like. If you spend all your time shooting a dSLR in automatic modes, you will get typical results that slightly exceed higher-end P&S at best, and are significantly degraded otherwise. If you're going to take the time to carry a bulky dSLR around, it's important to establish a working familiarity with the tool.

Here's a very simple example, which I previously posted in the General Photography thread:

This image would not have been possible using a walk-around lens and automatic settings. Although the bird feeder was only about three meters away, it was in the shade, and had a lot of brightly-lit, distracting details in the background (such as that truck parked on the street). Past experience, including lots of time spent shooting "crap #$% pictures that nobody will give a flying !@#$#@ about", had taught me that what I needed here was a long telephoto and a low aperture to control the depth of field and soften out the background. So, I took time to swap out my Tokina 80-200mm f/2.8, then set the aperture to 3.2 in Av mode, verified that the camera wasn't trying to set the exposure time too slow for the lens (else I would have made further adjustments to compensate), and then shot five frames in succession. Result? Exactly two of them achieved the best balance of view angle, and just one managed to catch one of the birds in flight.

Composition is very important. But so is knowing your tools and picking the right one for the job, and the only way to get good with a tool is to practice with it. In this case, I probably should have gone to f/4 or f/5.6 to sharpen up those birds a bit more, as the impact on DoF would have been minimal in this composition. Lesson learned for next time.